Antibacterial activity and photocatalytic dye degradation of copper oxide nanoparticles (CuONPs) using Justicia gendarussa

CuO nanoparticles' effect on the photosynthetic performance in seed tissues of Inga laurina (Fabaceae)

Copper oxide nanoparticles (CuONPs) have been produced on a large scale because they can be applied across various fields, especially in nano-enabled healthcare and agricultural products. However, the increasing use of CuONPs leads to their release and accumulation into the environment. The CuONPs uptaken by seeds and their implications on germination behavior have been reported, but little is known or understood about their impact on photosynthesis in seed tissues. To fill knowledge gaps, this study evaluated the effects of CuONP concentrations (0-300 mg L-1) on the photosynthetic activity of Inga laurina seeds. The microscopy data showed that CuONPs had an average size distribution of 57.5 ± 0.7 nm. Copper ion release and production of reactive oxygen species (ROS) by CuONPs were also evaluated by dialysis and spectroscopy experiments, respectively. CuONPs were not able to intrinsically generate ROS and released a low content of Cu2⁺ ions (4.5%, w/w). Time evolution of chlorophyll fluorescence imaging and laser-induced fluorescence spectroscopy were used to monitor the seeds subjected to nanoparticles during 168 h. The data demonstrate that CuONPs affected the steady-state maximum chlorophyll fluorescence (F m ' ), the photochemical efficiency of photosystem II (F v / F m ), and non-photochemical quenching ( NPQ ) of Inga laurina seeds over time. Besides, the NPQ significantly increased at the seed development stage, near the root protrusion stage, probably due to energy dissipation at this germination step. Additionally, the results indicated that CuONPs can change the oscillatory rhythms of energy dissipation of the seeds, disturbing the circadian clock. In conclusion, the results indicate that CuONPs can affect the photosynthetic behavior of I. laurina seeds. These findings open opportunities for using chlorophyll fluorescence as a non-destructive tool to evaluate nanoparticle impact on photosynthetic activity in seed tissues.

Electro-sensing layer constructed of a WO3/CuO nanocomposite, for the electrochemical determination of 2-phenylphenol fungicide

The abstract highlights the development of an electroanalytical sensor for the detection of 2-phenylphenol (2-PPL) as a contaminant. The novelty of the experiment lies in the utilization of a 1-D nanostructured WO3/CuO nanocomposite integrated with a carbon paste electrode (CPE). The hydrothermal method was used to synthesize the WO3 NPs, which were then characterized using Scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDS) techniques. Tungsten oxides (WO3) have been the subject of extensive study because of their many desirable characteristics, including their ease of preparation, tunable stoichiometry, crystal structure, particle morphology, 2.6 eV bandgap, excellent photocatalytic oxidation capacity, non-toxic nature, and widespread availability. The narrow band gap in CuO makes it an ideal sensing material. Copper oxide has applications in many different industries because it is a semiconductor metal with a narrow band gap in the spectrum of 1.2-1.9 eV and unique optical, electrical, and magnetic properties. Techniques like cyclic voltammetry (CV), and square wave voltammetry (SWV) were used. Real sample analysis was carried out in real-world samples like different types of soil, vegetables, and water. The electroanalytical sensor showed outstanding catalytic behavior by enhancing the peak current of the 2-phenylphenol with the potential shift to the less positive side compared to the unmodified carbon paste electrode in the presence of pH 7.0 phosphate buffer solution (PB). Throughout the experimental study, double distilled was used. Various electro-kinetic parameters like pH, accumulation time study, scan rate, concentration variation, standard heterogeneous rate constant, and participation of electrons, accumulation time, and transfer coefficient have been studied at WO3/CuO/CPE. The limit of detection was quantified together with the limit of quantification. Possible electrochemical oxidation mechanism of the toxic molecule was depicted. Overall, this research contributes to the field of electroanalytical sensing and offers potential applications in environmental monitoring.

Facile synthesis of CuONPs using Citrus limon juice for enhancing antibacterial activity against methicillin-resistant Staphylococcus aureus, beta-lactamase and tetracycline-resistant Escherichia coli

Antimicrobial resistance (AMR) resulting from indiscriminate use of antibiotics in various fields of agriculture such as livestock farming, aquaculture, and croup fields become an emerging catatroph for the health (human, animal) and environment. Among those, poultry farming has been considered as one of the major contributors of multidrug-resistant (MDR) bacteria. Focusing this, the present research is designed for green synthesis of copper oxide nanoparticles (CuONPs) with the aim of their application in antibiotic-free poultry farming for curving use of antibiotics in that sector. For that, antibacterial CuONPs were nanoformulated to decrease the required doses of bulk CuSO4. We used a CuSO4·5H2O solution as a Cu2+ source and Citrus limon juice as a reducing agent as well as capping agent. Particle yield was initially confirmed by the λmax specific to CuONPs (295 nm) using UV-Vis spectroscopy. The presence of the Cu-O group during particle formation and crystallinity with the purity of yielded NPs was confirmed with Fourier-transform infrared spectroscopy and X-ray diffractometry. The round to spherical CuONPs of 92-155 nm average size was confirmed with atomic force, scanning electron, and transmission electron microscopy. The concentration of yielded NPs was calculated with the dynamic light scattering. The physical characterization tools indicated a maximum CuONPs yield with a 0.001 M ion source with 15% reducing agents after 12 h reduction. Antibacterial effectivity was tested against methicillin-resistant Staphylococcus aureus and tetracycline- and beta-lactamase-resistant Escherichia coli, confirmed by PCR amplicon band at 163 bp, 643 bp, and 577 bp for the mecA, blaTEM-1 and tetA genes, respectively. An antibiogram assay of CuONPs showed a maximum zone of inhibition of 26 ± 0.5 mm for the synthesized particles. The minimum inhibitory and bactericidal concentrations were 1.6 μg ml-1 and 3.1 μg ml-1, respectively, for broad-spectrum application. Finally, the biocompatibility of CuONPs was determined by demonstrating a nonsignificant decrease of BHK-21 cell viability at <2 MIC doses for complying their future in vivo applicability.

Biogenic Synthesis of Copper Nanoparticles: A Systematic Review of Their Features and Main Applications

Nanotechnology is an innovative field of study that has made significant progress due to its potential versatility and wide range of applications, precisely because of the development of metal nanoparticles such as copper. Nanoparticles are bodies composed of a nanometric cluster of atoms (1-100 nm). Biogenic alternatives have replaced their chemical synthesis due to their environmental friendliness, dependability, sustainability, and low energy demand. This ecofriendly option has medical, pharmaceutical, food, and agricultural applications. When compared to their chemical counterparts, using biological agents, such as micro-organisms and plant extracts, as reducing and stabilizing agents has shown viability and acceptance. Therefore, it is a feasible alternative for rapid synthesis and scaling-up processes. Several research articles on the biogenic synthesis of copper nanoparticles have been published over the past decade. Still, none provided an organized, comprehensive overview of their properties and potential applications. Thus, this systematic review aims to assess research articles published over the past decade regarding the antioxidant, antitumor, antimicrobial, dye removal, and catalytic activities of biogenically synthesized copper nanoparticles using the scientific methodology of big data analytics. Plant extract and micro-organisms (bacteria and fungi) are addressed as biological agents. We intend to assist the scientific community in comprehending and locating helpful information for future research or application development.

Recent advances in adsorption of environmental pollutants using metal-organic frameworks-based hydrogels

Water pollution is increasing significantly owing to industrialization and population growth that lead to serious environmental and health issues. Therefore, the design and development of more effective wastewater treatment approaches are necessary due to a significant upsurge in demand for freshwater. More recently, metal-organic frameworks (MOFs) have attracted attention in environmental science owing to their tunable porosity, unique structure, flexibility, and various composition. Despite these attractive advantages, some drawbacks, including intrinsic fragility, unsatisfied processability, dust formation, and poor reusability, have greatly limited their applications. Therefore, MOFs are often designed as supported-based MOFs (e.g., MOFs-coated composites) or 3D structured composites, such as MOFs-based hydrogels. MOFs-based hydrogels are excellent candidates in the sorption process because of their appropriate adsorption capacity, porous structure, good mechanical properties, durability as well as biodegradable features. In this review, the removal of different pollutants (e.g., synthetic dyes, phosphates, heavy metals, antibiotics, and some organic compounds) from aqueous media has been studied by the adsorption process using MOFs-based hydrogels. The important advancements in the fabrication of MOFs-based hydrogels and their capacities in the adsorption of pollutants under experimental conditions have been discussed. Finally, problems and future perspectives on the adsorption process using MOFs-based hydrogels have been investigated.

Recent advances on botanical biosynthesis of nanoparticles for catalytic, water treatment and agricultural applications: A review

Green synthesis of nanoparticles using plant extracts minimizes the usage of toxic chemicals or energy. Here, we concentrate on the green synthesis of nanoparticles using natural compounds from plant extracts and their applications in catalysis, water treatment and agriculture. Polyphenols, flavonoid, rutin, quercetin, myricetin, kaempferol, coumarin, and gallic acid in the plant extracts engage in the reduction and stabilization of green nanoparticles. Ten types of nanoparticles involving Ag, Au, Cu, Pt, CuO, ZnO, MgO, TiO₂, Fe₃O₄, and ZrO₂ with emphasis on their formation mechanism are illuminated. We find that green nanoparticles serve as excellent, and recyclable catalysts for reduction of nitrophenols and synthesis of organic compounds with high yields of 83-100% and at least 5 recycles. Many emerging pollutants such as synthetic dyes, antibiotics, heavy metal and oils are effectively mitigated (90-100%) using green nanoparticles. In agriculture, green nanoparticles efficiently immobilize toxic compounds in soil. They are also sufficient nanopesticides to kill harmful larvae, and nanoinsecticides against dangerous vectors of pathogens. As potential nanofertilizers and nanoagrochemicals, green nanoparticles will open a revolution in green agriculture for sustainable development.